Mar.30 (GMM) At least five teams have already turned their attention to copying the Brawn-esque diffuser design, according to gossip as the Albert Park paddock packed up ahead of this week's dash to Malaysia.

The appeal against the stewards' decision to allow the controversial diffusers to race in Australia will only be heard in Paris next month, but it is rumoured that BMW, Red Bull, McLaren, Ferrari and Renault are resigned to going down the path of readying for a negative outcome.

"For us it is not really possible to copy it," BMW's Nick Heidfeld told the German news agency SID, "because not everything on our car can be changed at short notice."

Red Bull's Christian Horner added: "The ramifications could be the whole rear half of the car which obviously has a huge amount of cost implications in a not fantastic economic time."

Whispers indicate McLaren is quite advanced with a 'double decker' diffuser design, and the Spanish newspaper Marca said Renault - despite boss Flavio Briatore's anger - is also working on the issue.

The sports newspaper said the same is true for Ferrari, while Fernando Alonso could be racing a new diffuser by the time of next month's Chinese grand prix.

"What is happening with the diffusers is stupid, forcing teams to spend money in a time of crisis," Briatore fumed.

"It is also about safety: we have already put similar pieces in our wind tunnel and it gives 14 per cent more downforce. That is not in the spirit of the regulations.

"(And) once they are developed we could be talking 30 or 40 (per cent additional)," Briatore added.

"The diffuser issues opens up a development path that was not previously open. That is potentially big performance gain because the floor is the most powerful aerodynamic tool on the car," Horner added.